Meerkat reproduction paper

Question 1

Why might dominant females surpress subordinate reproduction in cooperative breeders as a principle assumption - meerkat paper

Answer 1

Subordinates may be a resource themselves (caring for dominant offspring) which becomed depleted when they invest in their own offspring

Question 2

How do dominant females surpress subordinate reproduction? - meerkat paper

Answer 2

Targeted aggression

Temporary eviction

Infanticide

Question 3

What are dominant female attacks restricted to in cooperate breeders?

Answer 3

Subordinates who are more likely to breed

Periods when resource competition peaks - so offspring of dominants may be at a disadvantage

Avoided when subordinate retaliation is likely to be effective

Question 4

What is a secondary assumption for supressing subordinate reproduction?

Answer 4

Attempting to exert control over distribution of reproduction is costly and can reduce own output

Question 5

What is some evidence for both assumptions?

Answer 5

Principle assumption:

• limited to observations that subordinate breeding is sometimes asspciated with reduced dominant female success (offspring survival, weight)

Secondary assumption:

• restricted to a few observations of declines in offspring quality of dominants and the quality of care they receive

Hard to rule out correlations with other social or ecological variables

Question 6

How were the methods carried out?

Answer 6

Ran over two years

Rainfall was imputed daily

All animals tagged for identification

Mass was recorded regularly

138 females were involved

Injected subordinate females were contraceptive

Question 7

What were the control and treatment groups in the meerkat paper?

Answer 7

Treatment:

• all subordinates over 180 days old were given contraceptive

Control:

• all subordinates were injected with equivalent volume of saline solution

Question 8

What were the results found to be in the meerkat paper?

Answer 8

Some females from control groups conceived whereas none in treatment

Experiment affected 59 dominant breeding attempts

In treatment groups, dominant females attacked subordinates less, were more tolerant of subordinate presence, less likely to interupt subordinate’s foraging and less likely to be evicted

Ratio of female helpers to pups greater in treatment (less likely to be evicted) which likely to have positive effects on pup development

Dominant female foraging efficieny higher in treated groups and had more weight gain and pups born were heavier - so subordinate breeding has negative effects on dominant

Subordinate females provided more food as not putting energy towards own reproduction

Pups in treated groups grew faster which improves future fitness

Question 9

What can be concluded from the discussion of the meerkat paper?

Answer 9

Results confirm principle assumption - domiants surpress subordinate reproduction because it reduces dominant’s fitness

Results also confirm controlling subordinate breeding is costly - treatment domiants foraged better and gained more weight

Because it is costly, dominants may play tactics to reduce subordinate breeding rather than just attacking, such as denying access to unrelated members of opposite sex and exaggerating power asymmetries

Also shows why plural breeding is rare in cooperative breeding vertebrates - only when social structure limits direct competition between offspring